The Amanita muscaria mushroom primarily grows in woodland areas in leaf litter. The color of the mature cap (pileus) ranges from a striking red to yellow or orange. The cap is noted for having scattered “flakes” (scales) on the top surface, which are remnants of its protective covering (veil or volva) that it grows through its maturing process. In the mature mushroom, these scales can appear to be in concentric circles. Although not seen in this image, the stem (stipe) would have a skirt (ring) of tissue around it and have a rough appearance at the bottom third. Under the cap, this species has laminae-free white gills and white spores.1

Toxins

The toxins are primarily ibotenic acid and muscimol. These chemicals have GABAergic and glutamatergic effects (agonist to glutamate and GABA receptors). The symptoms of A. muscaria poisoning include nausea and vomiting, somnolence, dizziness, hallucinations, dysphoria, delirium, ataxia, myoclonic movements, and seizures.

The 2016 Annual Report of the American Association of Poison Control Centers’ National Poison Data System shows almost 6,000 calls to poison centers about mushroom exposures but only four deaths.

A. muscaria is commonly known as fly agaric. This is because the cap can be placed in a saucer with milk, which both attracts and kills flies that drink the liquid.

Myths

Although deaths are uncommon, exposures and illnesses from mushroom ingestions are not rare. There are many myths that purportedly assist neophyte mushroom hunters in differentiating poisonous mushrooms from edible ones. Myths include that safe mushrooms have a pileus (cap) that can be peeled or grow on a certain side of a tree; that poisonous mushrooms cause a silver spoon or an onion to turn black while they are being cooked or burn your mouth when you eat them; that cooking the mushroom inactivates the poison; and that insects only land on safe mushrooms. None of these myths are true.

History and Popular Culture

The mushroom has a long history of being used in religion, particularly in Asia. It has been used in a sacred and hallucinogenic ritual drink called soma for more than 4,000 years. It has also been the topic of a Hindu religious hymn. Interestingly, muscimol is excreted in the urine of those intoxicated with the mushroom, leading to followers seeking to drink the urine for its hallucinatory properties.

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About the Author

Dr. Hack (Oleander Photography) is an emergency physician and medical toxicologist who enjoys taking photographs of beautiful toxic, medicinal, and benign flowers that he stumbles upon or grows in his garden. Contact him at ToxInRI@gmail.com.